is the problem that you don't have fast enough internet, or that you don't have internet at all at a particular time?
if your internet is super loving slow, look into using a git repository. it uses a "delta" updating system so it only works with the
changes in files, rather than the whole thing, saving bandwidth. perfect for code. additionally, other people can "push" changes which you can review and accept, allowing people to easily collaborate on the project.
downsides: it's a new paradigm of thinking for someone not familiar with it, and is a little complicated. this is pretty handy for remedying that problem though:
http://rogerdudler.github.io/git-guide/if you don't have internet at all I can't help you.